Chuck device for power tool

Abstract

A chuck device for a power tool includes a follower rotatably and slidably received in a tube and coupled to and driven by a power tool and having a hole for receiving a driving stem. One or more balls are slidably received in the follower and may be forced inward of the follower to engage with the driving stem for allowing the driving stem to be driven by the follower. The balls may be disengaged from the driving stem when the ball is received in the annular recess of the tube for preventing the driving stem from being over-driven by the power tool.

I claim: 
     
       1. A chuck device for a power tool, said chuck device comprising: a tube including an annular recess formed therein,   a follower rotatably and slidably received in said tube, said follower including a first end having a hole formed therein and including a second end for coupling to and for being driven by the power tool, said follower including a middle portion having at least one orifice formed therein and including at least one first ball slidably received in said at least one orifice and movable inward of said follower,   a driving stem rotatably received in said follower and including a first end for engaging with and for driving a fastener,   said at least one first ball being forced inward of said hole of said follower to engage with said driving stem for allowing said driving stem to be driven by said follower, and said at least one first ball being disengaged from said driving stem when said follower is moved relative to said tube until said at least one first ball is received in said annular recess of said tube for preventing said driving stem from being over-driven by the power tool,   means for disengaging said at least one first ball from said annular recess of said tube,   means for rotatably securing said driving stem in said hole of said follower, and   a barrel secured to said tube and close to said first end of said follower, a chuck slidably received in said barrel for retaining the fastener, and means for biasing said chuck away from said first end of said follower to retain the fastener.   
     
     
       2. The chuck device according to claim 1, wherein said at least one first ball disengaging means includes a cap secured to said second end of said follower and means for biasing said cap and said second end of said follower away from said tube to disengage said at least one first ball from said annular recess of said tube. 
     
     
       3. The chuck device according to claim 1, wherein said driving stem rotatably securing means includes an annular groove formed in said tube, an annular groove formed in said driving stem, an aperture formed in said follower, a second ball slidably received in said aperture of said follower and engaged in said hole of said follower for engaging with said annular groove of said driving stem and for rotatably securing said driving stem in said hole of said follower, said second ball is disengaged from said annular groove of said driving stem when said second ball is received in said annular groove of said tube.